It may sound like a fantasy straight out of "Jurassic Park." But it was a real scientific breakthrough that's said to have inspired Michael Crichton's bestseller. In 1984 the quagga, a South African zebra with stripes on the front half of its body that's been extinct since 1883, became the first extinct animal from which scientists extracted DNA using preserved specimens.

"It started when a local taxidermist by the name of Reinhold Rau thought it might be feasible to rebreed the quagga using living plains zebras by choosing some of the lesser-striped ones," said geneticist Eric Harley. Harley has been a scientific advisor to the group, The Quagga Project, since its inception a quarter-century ago.

The project hinges on the idea that the quagga is not a separate species, rather a subspecies of the plains zebra. If so, Harley said, "it means that the genes may still be there in the current living population of plains zebra animals, but in a diluted form. By concentrating them using selective breeding, we can get back animals showing the full appearance of the original quagga."

After four generations of breeding, Dr. Harley and his team said they'd done just that. These animals -- quaggas 2.0 -- roam Elandsberg Nature Reserve, in South Africa.

"People get really excited about the quaggas because here is an example of where an animal was thought to be extinct, totally gone and not on Earth," said Bernard Wooding, reserve manager at the preserve. "We've managed to rebreed it and bring it back again. It's available to be seen by all -- a unique and very exciting thing."

But are these zebra-like creatures really quaggas?

Dr. Robert Fleischer, head of the genetics program at the Smithsonian Institute's National Museum of Natural History, questioned the premise that quaggas are a subspecies of zebra. He has studied quagga DNA from more than a dozen specimens in museums around the world. He said quaggas may have been isolated from other zebra subspecies for 200,000 years or so.

"If that's the case," he said, "there may have been other genetic aspects that kept them from interbreeding regularly, and they may have actually been a distinct species. The taxonomy is a bit muddy."

Harley added: "What we are doing is retrieving an animal which has the physical appearance of the quagga. Indeed, it may not have all the full genetic qualities of the original quagga, but on the other hand, there's no particular reason to suppose that the quagga had any particular characteristics which made it different from other plains zebras, other than its lack of striping."

Fleischer had no quarrel with introducing the new animals into the zebra habitat.

"But," he added, "if they're trying to make the claim that they're restoring this exact species, I think that's falling short."

Even partial success sustains the fantasy that woolly mammoths -- maybe even dinosaurs -- will stalk the earth once more.

"Years ago, I would have said it's quite impossible," said Harley. "Now, it is just within the bounds of foreseeable possibility."

Fleischer admitted: "The science fiction nerd in me thinks this is really interesting and fascinating and it would be great to have something like this."

But he couldn't shake the practical -- and moral -- questions: "But the science nerd, and the training and the conservation nerd, thinks maybe this is something that isn't that feasible. And even if it is that feasible, do we really need to do it, or should we do it?"